AD7873ARQZ

Overview

The AD7873ARQZ is a 12-bit successive approximation analog-to-digital converter (ADC) designed for resistive touch screen digitizer applications. It operates from a single 2.2 V to 5.25 V supply and supports throughput rates up to 125 kSPS. The device integrates on-chip switches, a 2.5 V reference, and a temperature sensor. Key specifications include a maximum integral nonlinearity of ±1 LSB (AD7873B1 variant), an input voltage range of 0 V to VREF, and a shutdown mode with current consumption below 1 µA. It utilizes a high-speed synchronous serial interface.

Feature Summary

• Integrated 4-wire touch screen interface with low on-resistance switches
• On-chip 2.5 V reference and temperature sensor (-40°C to +85°C)
• Direct battery measurement capability (0 V to 6 V)
• Programmable resolution (8-bit or 12-bit) via serial control register

Applications

• Personal digital assistants
• Smart hand-held devices
• Touch screen monitors
• Point-of-sale terminals
• Pagers

Procurement Notes

Verify the specific grade suffix (e.g., ARQZ vs BRQZ) against the required accuracy parameters such as Integral Nonlinearity. Confirm package availability, as the QSOP-16 form factor may have limited stock compared to other variants in the series. Ensure the ordering suffix matches the desired thermal and electrical specifications defined in the manufacturer's official documentation.

Selection Notes

Select the AD7873ARQZ for applications requiring ratiometric conversion to eliminate errors from switch resistances. Choose this component over the AD7843 if integrated battery monitoring and temperature sensing are required. Ensure the system clock frequency does not exceed 2 MHz to maintain the specified 125 kSPS throughput rate. Verify that the external source impedance allows for sufficient acquisition time within the three DCLK cycle constraint.

Part Context

The AD7873 belongs to the Analog Devices AD7873 family of touch screen controllers. It shares functional similarities with the AD7843 but adds dedicated hardware for battery voltage and die temperature measurement. The ARQZ designation indicates the commercial temperature range version packaged in a 16-lead Quarter Size Outline Package (QSOP).

Replacement Considerations

Public confirmed substitute part numbers: AD7873BRQZ.